This invention relates to bag valve coupling members for the collapsible bags of bag-in-box containers such as are used for soft drink syrups, and in particular to a back-flow preventing valve therefor.
Bag valve coupling members (known as bag valves) for bag-in-box containers are well-known, as shown, for example, in U.S. Pat. No. 4,445,539. Although these containers are intended for single use only, empties of such bags have been back-filled through the bag valve and hose connector, under possibly unsanitary conditions, with the syrup of third parties and re-sold (or palmed off) to unsuspecting purchasers as the original product.